ErikwithAK01

So I recently found a place to get good gas, because I thought that was the end all to be all of my low poor woes (which it was to a degree, considering I don't run in knock retard timing under WOT anymore), but it wasn't. Still having a rough idle for a stock cam, and still not feeling quite right in the seat of the pants, I figured lets do plugs and wires! I detailed my engine bay Sunday when it was beautiful out, and discovered that the stock wires were looking their age at 75K, and that the plugs probably did as well. I ordered GMPP red hot wires from the local dealer, and a new set of Iridium AC-Delco's while I was at it. and installed them tonight...THIS is what I found the gap on the Denso spark plugs that came out were just north of 0.065"!!! Needless to say, the car runs WAY smoother now, and definitely picked up the missing power. I am right where it feels I should be now

Todds427

I think the stock gap was .060 for that year, but was probably a good time to change them!

ErikwithAK01

GM changed the plug design and gap specs for all gen III engines mainly due to idle instability, as per TSB 30604060, but what they do not tell you, is that their OE equipped platinum plugs had issues with the platinum tips falling off in use, causing a huge open gap and cold spark, iridium plugs gapped at .040" are the new GM recommendation. Whoever did the plugs on my car last used $1.80 cheapos to save some money after (im assuming) having the issue with thd plug tips coming off and made the car run terrible, you shoulda seen the ones I pulled, the electrode was worn down to the insulator so they must have been pretty old.

Todds427

I haven't found a better plug then the iridium plugs. They work very well and sounds like you got a new car out of the deal!

ErikwithAK01

Seriously, the difference was WOW! Which is good since they're 96 bucks a set xo

RED99

Iridium are best for longevity. But believe it or not, they are not the best for the best spark! Iridium has far less conductivity than copper. They will also run hotter. Which isn't going to help if you have a knock retard problem.
The Denso doesn't look like a Iridium or platinum spark plug! Which isn't going to have the longevity and will wear faster. .065" gap is getting on out there.
If you are like me and don't like changing plugs, then iridiums are a good choice. lol Don't waste your money on the platnums.

ErikwithAK01

You are correct about the copper, but hand in hand, silver tipped I'd supposed to be the best, but it wears I believe even more rapidly. I know a friend of mine runs them in his ls6 powered 240sx drift car and he makes more power with them

Rocket-J

I changed mine today. Replaced like for like. The AC Delco Iridium came gapped at .044" so I used them as they came. All were the same.
The plugs that came out had .075" gaps with 30K miles on them. Don't know that anyone touch my car since I bought it new. No sign of burning or missing tips. It did have a tune 3 years ago. Maybe they reset my gap. I just don't know.


My photo is not as good as the ones above.

30K miles. .075 gap. AC Delco Iridium.

JETninja

I run Copper ones in my M3, its very easy to change them and I get pretty good mileage out of them. The Vette still has what it came with, but I ordered new wires from Hinson and tomorrow will order (Payday) from Amazon NGK Iridiums ($45 a set) and wire heat shields (($19) since it has 55k on it I figured good time to change them.

ErikwithAK01

Way to revive a 2 year old thread there